Behavior of High Strength Reinforced Concrete Hollow Circular Short Columns under Axial Loads

Abstract

This work deals with investigating the capacity of high strength columns, under axial compression loads. A total of nine circular column with 600 mm length and 150 mm outer diameter were tested, three of them were solid as a reference, the remaining six columns were with internal hole of 50 and 75 mm dimeter. The effect of hole size as well as area of longitudinal steel reinforcement was studied. Area of steel used where 0, 301 and 471 mm² and two hole size were 50 and 75 mm. The results showed that the increasing of longitudinal reinforcement ratio from 0 % (plain) to 2.67% (steel reinforcement area of 471 mm²) for solid column cause an increase in the ultimate strength by 33.6%, while for hollow columns with 75 mm internal hole the ultimate strength increased up to 33.2 %. Increase in hole dimeter from 50 to 75 mm caused a reduction of columns capacity in all cause, the decrease was up 33 % for columns with 301 mm² steel area was up to 32 %, for columns with 417 mm²